Not able to call a function from itself after an interval - ios

Question

I want to keep calling following function for 'n' number of times, I'll write that code later. Now am facing a problem.
func keepHighlighting(myLbl : UILabel)
{
myLbl.text = "hi"
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for : indexPath) as! TableViewCell
let mySelector = #selector(self.keepHighlighting(duaLbl : cell.tempLbl))
let timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: mySelector, userInfo: nil, repeats: true);
timer.fire()
return cell
}
Error:
Argument of '#selector' does not refer to an '#objc' method, property, or initializer

Answer 1

You've misunderstood selectors. self.keepHighlighting(duaLbl : cell.tempLbl) is a function call. A selector is the name of a method (it's technically a message, but those generally resolve into a method call).
You cannot pass parameters via a selector. The method you're calling from a timer should have the signature void someMethod(_ timer: Timer). For that, the selector would be #selector(someMethod). (That compiles down to someMethod:, but you generally won't have to deal with that fact.)
Depending on what you're trying to do here, there are several approaches, but it's not quite clear what you're trying to do. My recommendation, though, is to put this logic into the cell itself rather than trying to manage it from the controller. It is generally much easier to have each cell manage its own behaviors than try to have the controller keep track of every cell and tweak it.

Answer 2

You have to annotate your method with #objc and use the Timers userInfoto parse arguments:
#objc func keepHighlighting(timer:Timer)
{
let myLbl = timer.userInfo as! UILabel
myLbl.text = "hi"
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for : indexPath) as! UITableViewCell
let mySelector = #selector(self.keepHighlighting)
let timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: mySelector, userInfo: cell.tempLbl, repeats: true);
timer.fire()
return cell
}